Chromosome 3, Monosomy 3p

Chromosome 3, Monosomy 3p

National Organization for Rare Disorders, Inc.

Important

It is possible that the main title of the report Chromosome 3, Monosomy 3p is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

  • Chromosome 3, Deletion of Distal 3p
  • Chromosome 3, Distal 3p Monosomy
  • Monosomy 3p

Disorder Subdivisions

  • None

General Discussion

Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which the end (distal) portion of the short arm (p) of chromosome 3 is missing (deleted or monosomic). The range and severity of symptoms and findings may be variable. However, associated features often include growth delays before and after birth (prenatal and postnatal growth deficiency); severe to profound mental retardation; distinctive malformations of the skull and facial (craniofacial) region; eyebrows that grow together (synophrys); and/or excessive hair growth (hypertrichosis). Additional physical abnormalities may also be present. In many cases, Chromosome 3, Monosomy 3p appears to occur spontaneously (de novo) for unknown reasons.

Symptoms

As noted above, the symptoms and physical findings associated with Chromosome 3, Monosomy 3p may vary in range and severity from case to case. However, according to reports in the medical literature, many affected individuals have a low birthweight; marked growth delays after birth (postnatal growth retardation); severe to profound mental retardation; severe delays in the acquisition of skills requiring the coordination of mental and motor activities (psychomotor retardation); excessive hair growth (hypertrichosis); and/or distinctive malformations of the skull and facial (craniofacial) region.



Many affected infants have an abnormally small head (microcephaly) that may appear unusually short and broad (brachycephaly); a flat back region of the head (occiput); and/or an abnormally high, narrow, prominent forehead. Additional craniofacial abnormalities may include a triangular face; arched eyebrows that grow together (synophrys); a broad, flat nose; an unusually long vertical groove in the middle of the upper lip (philtrum); thin lips; and/or an abnormally small lower jaw (mandible). Affected individuals may also have a downwardly turned mouth; widely spaced eyes (ocular hypertelorism); vertical skin folds that cover the eyes' inner corners (epicanthal folds); upwardly slanting eyelid folds (palpebral fissures); drooping of the upper eyelids (ptosis); and/or low-set, malformed ears.



Chromosome 3, Monosomy 3p is also commonly associated with more than the normal number of fingers and/or toes (polydactyly). In many cases, there may be additional fingers, particularly duplication of the "pinkies" or fifth fingers (postaxial polydactyly). In addition, in some instances, affected infants may have duplication of certain toes, particularly the fifth toes.



Reports indicate that some affected individuals may also have hearing loss and/or visual impairment. In addition, the disorder may be associated with additional physical features, such as abnormal forward (anterior) placement of the anus; undescended testes (cryptorchidism) in affected males; kidney (renal) defects: structural malformations of the heart (congenital heart defects); and/or other abnormalities.

Causes

Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which there is deletion (monosomy) of the end (distal) portion of the short arm (p) of chromosome 3. Researchers indicate that symptoms and findings characteristic of the syndrome result from deletion of chromosomal material extending from band 25 on the short arm of chromosome 3 (breakpoint) to the end or "terminal" of 3p (3p25-->pter). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as "p" and a long arm identified by the letter "q". Chromosomes are further subdivided into bands that are numbered. Therefore, 3p25 refers to band 25 on the short arm of chromosome 3.



In most reported cases, Chromosome 3, Monosomy 3p has appeared to result from spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.



All cases of Monosomy 3p except for one have been new chromosomal changes (de novo). In one case, the deletion was inherited from the mother who had the same deletion 3p. Potentially, monosomy 3p could result from a parental translocation or inversion.



Translocations occur when regions of certain chromosomes break off and are interchanged, resulting in shifting of genetic material and an altered set of chromosomes. If such chromosomal rearrangements are "balanced", all of the chromosomal material is present in two copies but at different locations. Balanced translocations are usually harmless to the carrier. However, such chromosomal rearrangements may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring if inherited in an "unbalanced" state. An unbalanced translocation occurs when only one of the two chromosomes involved in the translocation is inherited from a carrier parent. The result is too much (duplication or trisomy) or too little (deletion or monosomy) chromosomal material. An inversion occurs when a chromosome breaks in two places within a single chromosome and the segment between the breaks rejoins the chromosome in the reverse order. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude a chromosomal rearrangement in one of the parents.

Affected Populations

Chromosome 3, Monosomy 3p appears to affect males and females in relatively equal numbers. Since the disorder was originally reported in 1978 (Verjaal M), approximately 34 cases have been described in the medical literature.

Standard Therapies

Diagnosis

In some cases, Chromosome 3, Monosomy 3p may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 3p.



The disorder may also be diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic findings (e.g., growth delays, mental retardation, psychomotor retardation, craniofacial abnormalities, etc.), and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder.



Treatment

The treatment of Chromosome 3, Monosomy 3p is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; neurologists; physicians who diagnose and treat heart abnormalities (cardiologists); hearing specialists; and/or other health care professionals. In some cases, physicians may recommend surgical repair of certain malformations associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.



Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for families of affected children. Other treatment for this disorder is symptomatic and supportive.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.



For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:



Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov



For information about clinical trials sponsored by private sources, contact:

www.centerwatch.com.

References

TEXTBOOKS

Jones KL. Smith's Recognizable Patterns of Human Malformation. 5th ed. Philadelphia, PA; W.B. Saunders Company; 1997:34-35.



Buyse ML. Birth Defects Encyclopedia. Dover, MA; Blackwell Scientific Publications, Inc.; 1990:332.



Gorlin RJ, et al., eds. Syndromes of the Head and Neck. 3rd ed. New York, NY; Oxford University Press; 1990:72.



JOURNAL ARTICLES

Kariya S, et al. A terminal deletion of the short arm of chromosome 3: karyotype 46, XY, del (3) (p25-pter); a case report and literature review. Int J Pediatr Otorhinolaryngol. 2000;56:71-78.



Angeloni D, et al. CALL gene is haploinsufficient in a 3p- syndrome patient. Am J Med Genet. 1999;86:482-85.



Benini D, et al. 46, XY, del (3) (pter-->p25) syndrome: further delineation of the clinical phenotype. Eur J Pediatr. 1999;158:955-57.



Lukusa T, et al. A 3p deletion syndrome in a child with both del(3)(p25-->pter) and dup(17)(q23-->qter). Ann Genet. 1999;42:91-94.



Narahara K, et al. Loss of the 3p25.3 band is critical in the manifestation of del(3p) syndrome: karyotype-phenotype correlation in cases with deficiency of the distal portion of the short arm of chromosome 3. Am J Med Genet. 1990;35:269-73.



Schwyzer U, et al. Terminal deletion of the short arm of chromosome 3, del(3pter-p25): a recognizable syndrome. Helv Paediatr Acta. 1987;42:309-15.



Tolmie JL, et al. Partial deletion of the short arm of chromosome 3 [letter]. Clin Genet. 1986;29:538-40.



Higginbottom MC, et al. A second patient with partial deletion of the short arm of chromosome 3: karyotype 46,XY,del(3)(p25). J Med Genet. 1982;19:71-73.



Verjaal M, et al. A patient with a partial deletion of the short arm of chromosome 3. Am J Dis Child. 1978;132:43-45.

Resources

Children's Craniofacial Association

13140 Coit Road

Suite 517

Dallas, TX 75240

USA

Tel: (214)570-9099

Fax: (214)570-8811

Tel: (800)535-3643

Email: contactCCA@ccakids.com

Internet: http://www.ccakids.com



March of Dimes Birth Defects Foundation

1275 Mamaroneck Avenue

White Plains, NY 10605

Tel: (914)997-4488

Fax: (914)997-4763

Tel: (888)663-4637

Email: Askus@marchofdimes.com

Internet: http://www.marchofdimes.com



The Arc

1825 K Street NW, Suite 1200

Washington, DC 20006

Tel: (202)534-3700

Fax: (202)534-3731

Tel: (800)433-5255

TDD: (817)277-0553

Email: info@thearc.org

Internet: http://www.thearc.org



AmeriFace

P.O. Box 751112

Limekiln, PA 19535

USA

Tel: (702)769-9264

Fax: (702)341-5351

Tel: (888)486-1209

Email: info@ameriface.org

Internet: http://www.ameriface.org



Chromosome Disorder Outreach, Inc.

P.O. Box 724

Boca Raton, FL 33429-0724

USA

Tel: (561)395-4252

Fax: (561)395-4252

Email: info@chromodisorder.org

Internet: http://www.chromodisorder.org/CDO/



American Heart Association

7272 Greenville Avenue

Dallas, TX 75231

Tel: (214)784-7212

Fax: (214)784-1307

Tel: (800)242-8721

Email: Review.personal.info@heart.org

Internet: http://www.heart.org



NIH/National Eye Institute

31 Center Dr

MSC 2510

Bethesda, MD 20892-2510

United States

Tel: (301)496-5248

Fax: (301)402-1065

Email: 2020@nei.nih.gov

Internet: http://www.nei.nih.gov/



NIH/National Kidney and Urologic Diseases Information Clearinghouse

3 Information Way

Bethesda, MD 20892-3580

Fax: (703)738-4929

Tel: (800)891-5390

TDD: (866)569-1162

Email: nkudic@info.niddk.nih.gov

Internet: http://www.kidney.niddk.nih.gov/



NIH/National Institute on Deafness and Other Communication Disorders

31 Center Drive, MSC 2320

Communication Avenue

Bethesda, MD 20892-3456

Tel: (301)402-0900

Fax: (301)907-8830

Tel: (800)241-1044

TDD: (800)241-1105

Email: nidcdinfo@nidcd.nih.gov

Internet: http://www.nidcd.nih.gov



UNIQUE - Rare Chromosome Disorder Support Group

P.O. Box 2189

Caterham

Surrey, CR3 5GN

United Kingdom

Tel: 4401883330766

Fax: 4401883330766

Email: info@rarechromo.org

Internet: http://www.rarechromo.org



Craniofacial Foundation of America

975 East Third Street

Chattanooga, TN 37403

Tel: (423)778-9176

Fax: (423)778-8172

Tel: (800)418-3223

Email: terry.smyth@erlanger.org

Internet: http://www.craniofacialfoundation.org



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/



For a Complete Report

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